A scanning electron microscope was indeed used to create this image of a real marijuana bud.
The original image was in black and white. The colors in this image are an artistic addition.
In July 2020, an image supposedly showing what a cannabis bud looks like under a scanning electron microscope (SEM) started to circulate on social media.
The object in the above-displayed image is truly a cannabis bud or flower, and this image was truly created with the use of a SEM. However, the colors present in this image are artistic additions.
This image was created circa 2016 by Ted Kinsman, an associate professor in the Photographic Sciences Department at Rochester Institute of Technology in Rochester, New York, with the use of a SEM. This microscope, however, only produces images in grayscale:
The scanning electron microscope (SEM) is widely used in various fields of industry and science because it is one of the most versatile imaging and measurement tools. Images produced are particularly appreciated for their high depth of field and excellent image resolution, both orders of magnitude better than light microscopy. However, images provided by the SEM are black and white, and single images contain information in only two dimensions. Of course grayscale images from an SEM are normal since this technology forms images with electrons instead of photons of visible light. Yet color is something important to us humans, and not just from an aesthetic point of view. For millions of years perception of color helped our ancestors to survive, for example by allowing them to distinguish a ripe fruit hidden amongst the green leaves of a tree. Color helps our brain to differentiate and identify objects. Thus our brains rely on color (and stereoscopic vision) to correctly perceive objects.
Once Kinsman had his SEM image, he was able to enhance it with vibrant colors in order to make it more appealing.
Tech Insider did a video about Kinsman's work in 2018. The science outlet explained that "each image starts out as black and has to be colorized by hand. ... Ted paints the THC-containing Cannabis sacs a bright color in order to stand out."
Kinsman added: "I pick visually exciting colors because I'm trying to make science visually exciting and appealing to the general population."
Here's a video about Kinsman's work:
Several similar images can be found in Kinsman's book "Cannabis: Marijuana under the Microscope."